168 REV. PROF. G. HENSLOW ON THE 
six styles, it looks as if other cords might be marginal as well, 
but are now arrested so as simply to supply the wall of the ovary, 
just as do the alternate branching systems of Papaver. 
III. CRUCIFERÆ (Pl. XXIV.).—vrr. CHEIrANTHUS CHEIRI. 
The pedicel of a Wallflower has five cords (1). These multiply 
and change from a circular to an elliptical arrangement (2, 3). 
The two cords at the extremities of the long axis are the first to 
pass off to supply the Zateral sepals (4); not the antero-posterior 
pair, whieh, although overlapping the lateral sepals iu estivation, 
receive their cords after them (5). The section now shows a 
quadrangular arrangement, the four corners supplying the four 
petals with their cords (5, 6, 7, p-), While fresh ones appear 
superposed to the lateral sepals by the closing up of the cylinder. 
These now prepare for the two shorter stamens (6, l.st.). The 
glands (G) appear between tlıe sepals aud these stamens. The 
cords for the taller pair now appear close beside those of the 
petals (6, 7, p.st.) ; while another group of tracheæ stands be- 
tween the two cords which belong to the taller pair of stamens 
(7, pl.). This group becomes the marginal cords of a carpel. 
I have italicized the words above in order to emphasize the 
fact that the pairs of longer stamens are not due to chorisis from 
an originally single stamen, as there is a cluster of carpellary 
tracheæ between them, as shown in figures 7 and 8. 
The pistil is provided for by the £wo groups, one from each, 2. e., 
the anterior and the posterior side (7, pl.), and two pairs of 
cords situated laterally. Their origins become clear, inasmuch 
as these lateral pairs had at first the staminal cord between them ; 
while the posterior and anterior carpellary cords stand between 
the two stamens of each of the larger pair. The pairs of lateral 
cords pass up into the valves (9, v.), while the others nourish the 
placentas and ovules (9, pl.). In the style, the latter have 
dwindled to minute cords, the former cords having become the 
larger ones (10). 
The disconnected origin of the tour carpellary groups coun- 
tenances the idea that they represent four carpels, as illustrated 
by Tetrapoma, which has four styles. This genus is therefore 
comparable in this respect to Eschscholtzia in the Papaveracee *. 
* I have discussed the origin of the binary and quaternary features of a 
Cruciferous flower in my work ‘On the Origin of Floral 
Structures,’ p. 31, to 
which I would here refer the reader; as well as ina paper * On the Structure 
of a Cruciferous Flower,” in Trans. Linn. Soc. 2nd ser. (Botany), vol. i. p. 191. 
